1. Field of the Invention.
The invention relates to an arrangement for adjusting the damping force on the piston of a hydraulic telescopic shock absorber having a cylinder in which the piston is movable by a piston rod and the damping force is determined by the position of a closure member that acts upon a passage in the piston. The invention enables the position of the closure member to be influenced by bringing an adjusting member in an end position of the piston in engagement with a stop member installed near the cylinder end surface, through which by turning the piston by means of the piston rod the turning along of the adjusting member is prevented and the position of the closure member relative to that of the piston may be changed. Means are also provided to bring the stop member out of reach of the adjusting member when desired to render the adjusting device inoperative.
2. Description of the Prior Art.
Such a device is known from the German Auslegeschrift 1.251.593, which matured on Apr. 4, 1968 into a patent having the same number U.S. Pat. No. 1,251,593. In this an adjusting device for a hydraulic shock absorber is described which uses a stop member situated on the inside of the cylinder and which engages an adjusting member connected to the piston during the adjusting in an end position of the piston. After having completed the adjustment, further engagement of the stop member and adjusting member is made impossible by additional parts. In this way, unwanted adjustment later on by an unqualified person or during the fitting in of the shock absorber in a vehicle is prevented in an excessive way.
However, this well known device has the disadvantage that the means to position the stop member out of reach of the adjusting member are formed by means which obstruct a part of the useful stroke of the shock absorber. A second disadvantage is that later readjustment of the damping force is not possible in a simple way, as the shock absorber has to be disassembled partly. Further, only one end position may be recognized perceptibly during the adjustment. Perceptible recognizable intermediate positions are not available.